With the increasing number of automobiles nowadays, we use petroleum casing when we are drilling for oil because it contains more of the corrosive substances in the crude oil, so it is necessary when we carry out the oil casing and note that when we use petroleum casing to extract oil, the casing will be very prone to corrosion. How should we prevent the casing from being corroded at this time? Then let me, to introduce you to the oil casing when used in how to carry out anti-corrosion. (1) When we use petroleum casing to transport water, we should ensure that the quality of the water is up to standard when it is used, the quality of the water should be up to standard, and when it comes to discharging implementation of the sewage disposal. In the use of the time to strengthen the cleaning of the main water pipe to ensure that the use of oil casing after the pipeline does not remain corrosive substances. Ensure that the oil casing can be longevity when used. (2) For injection wells that have already been put into production, we should take the work of adding some annular spacers to maintain them when we use them, and the regular addition of protective liquid like this should become a kind of system, we need to regularly add to the inside of the oil casing, the only way to ensure that the oil casing in use can be used for a long time. (3) In the use of oil casing, there will be mechanical abrasions, these scratches will affect the corrosion of oil casing, accelerate the corrosion of oil casing, it is recommended in the use of the time can be in the tubing coupling add a rubber ring on top of it to reduce corrosion of the oil casing.

1. Bushing: Mainly used for drilling in the sea and desert, to separate the seawater and sand and ensure the well drilling. The main specifications of this bushing are: ∮762mm (30in) × 25.4mm, ∮762mm (30in) × 19.06mm. 2. Surface casing: mainly used for the first time drilling, drilling soft surface ground to bedrock, in order to seal this part of the formation will not collapse, the need to use surface casing for sealing. The main specifications of the surface casing: 508mm (20in) 406.4mm (16in), 339.73mm (13-3 / 8in), 273.05mm (10-3 / 4in), 244.48mm (9-5 / 8in) and so on. Under the tube depth depends on the depth of the soft formation, usually 80 ~ 1500m. The external pressure and internal pressure are not large, generally use more K55 steel grade or N80 steel grade. 3. Technology casing: used in complex formation drilling process, when encountered in collapsed layer, oil layer, gas layer, water layer, leakage layer, salt paste layer and other complex parts, the need for technical casing sealing, otherwise drilling will not work. Some well deep and complex wells, and go down to a depth of several kilometers, this deep well requires several layers of technology casing, its mechanical properties and sealing performance requirements are high, the steel grade is also higher, in addition to K55, More is the use of N80 and P110 steel grade, some deep wells also use Q125 or even higher non-API grade such as V150. The main specifications of the technical casing are: 339.73mm (13-3 / 8in), 273.05mm (10-3 / 4in), 244.48mm (9-5 / 8in), 219.08mm (8-5 / 8in), 193.68mm (7- 5 / 8in), 177.8mm (7in) and so on. 4. Oil casing: when drilling the target layer (oil and gas layers), the need to use oil and gas casing casing layer bare exposed all of the upper seal, reservoir casing inside the tubing. Oil and gas casing in all types of casing depth down the deepest, its mechanical properties and sealing performance requirements are the highest.

Corrosion prevention measures of oil casing 1. Do a good job of water quality standards, strict water quality testing and management. The implementation of clean-up and dispensing, to strengthen the main water pipe cleaning work, so that the station, bottom water quality standards, reduce the introduction of corrosion ring into the annular space. 2. For the new injection wells that have been newly put into operation, an annular protective solution mainly consisting of sterilizing and sterilization is adopted, and a system is formed for regular dosing. 3. In view of the mechanical abrasion on the corrosion of oil casing accelerated, it is recommended to add a rubber ring on the tubing coupling or in a serious part of the well plus a centralizer to avoid pipe scratching in the course of the operation and water pipe casing and one side of the sleeve. 4. In view of the serious corrosion of scale bacteria and slow SRB growth and killing at high temperature, 100 ℃ high temperature water or water vapor may be periodically injected into the annulus to kill the scale SRB. 5. It is not recommended to promote the use of cathodic protection and album casing before the injection well casing corrosion has not been effectively controlled.

Casing are used to reinforce the borehole wall, both inside and outside diameter is much larger than the drill pipe; drill pipe is used to connect drill collars and drill bits, enough length to support the bit in the downhole operation. Casing is to reinforce the wall, but also the passage of oil from the ground to the ground, is a completion tool, that is, after drilling, cementing tools. The drill pipe is a tool in the drilling process is connected to transmit power and torque, connecting the square drill, drill collars, joints and so on. Length of 9.5m, the middle of the thin, both ends of the connector. Casing thread is fine british thread 8 teeth / 25.4mm, taper 1:16. Drill pipe joints are thick buckle, more models.

The technical specifications of galvanized pipe are as follows: 1, Galvanized steel pipe, the surface should be straight and smooth, there should be no cracks, scarring, delamination, dislocation, hard bend, burr, indentation and deep scribing. 2, Grades and chemical composition of galvanized steel pipe should be consistent with the provisions of GB 3092 black pipe steel grades and chemical composition. 3, The pipe wall should be marked marked material manufacturing standards and manufacturers. 4, The chemical composition of the content of the following requirements: carbon 0.14-0.22%; manganese 0.3-0.65%; phosphorus is not more than 0.045%; sulfur is not more than 0.05%. 5, The quality of galvanized steel pipe should be consistent with the "carbon structural steel" (GB / T700) in the Q235-A steel and JGJ130-2001 provisions. 6, Nominal diameter of not more than 50mm galvanized steel pipe should be cold bending test. Bending angle of 90 °, bending radius of 8 times the outer diameter. The test without filler, the sample should be placed in the weld bead bending direction of the outer or upper part. After the test, there should be no cracks on the specimen and peeling of the zinc layer. 7, Hydrostatic test should be carried out in the black tube, eddy current testing can also be used instead of hydrostatic test. Test pressure or eddy current test specimen size should be consistent with the provisions of GB 3092.